Add a core_scheduling option to --cpus with three modes of operation.
This feature takes advantage of a kernel feature that restricts
scheduling of processes on the SMT threads on the same core. This is
useful for mitigating certain classes of side-channel attacks and has
better performance that disabling SMT on the CPU.
- vm (default): All vCPU threads share one core scheduling cookie.
They may be co-scheduled on SMT siblings while host threads are
excluded - this has minimal performance impact and can even
potentially improve performance from co-location.
- vcpu: Each vCPU gets a unique cookie preventing any two vCPUs from
sharing SMT siblings. This has the strongest isolation but at some
compromise of performance.
- off: No core scheduling applied (old behaviour).
This isolation is done by the kernel maintaining a "cookie" - threads
with the same cookie can share the same core.
In vCPU mode each vCPU thread the cookie is created when the thread
starts and each gets a unique cookie. For VM mode the first vCPU thread
(the leader) will create the cookie. All other vCPU threads started (via
hotplug or during boot) will have that cookie shared to it.
EINVAL/ENODEV from prctl is silently ignored so this works transparently
on kernels older than 5.14 that lack PR_SCHED_CORE or when SMT disabled.
Full details of this kernel feature can be found at:
https://docs.kernel.org/admin-guide/hw-vuln/core-scheduling.html
This implementation was inspired by crosvm's implementation - in
particular the enable_core_scheduling() function.
This is challenging to test via integration testing but the logging of
the received cookie shows it working:
VM case:
cloud-hypervisor: 0.243102s: <vcpu1> INFO:vmm/src/cpu.rs:1247 -- vCPU 1: core scheduling cookie = 0x33e4c167
cloud-hypervisor: 0.243102s: <vcpu0> INFO:vmm/src/cpu.rs:1247 -- vCPU 0: core scheduling cookie = 0x33e4c167
vCPU case:
cloud-hypervisor: 0.089356s: <vcpu0> INFO:vmm/src/cpu.rs:1247 -- vCPU 0: core scheduling cookie = 0x13993ad6
cloud-hypervisor: 0.089380s: <vcpu1> INFO:vmm/src/cpu.rs:1247 -- vCPU 1: core scheduling cookie = 0xd48e86e
Signed-off-by: Rob Bradford <rbradford@meta.com>
Add an option in the CLI to enable nested support.
Adding an option --cpu nested=on|off to the CPU
argument to enable nested support for Microsoft
Hypervisor. By default it is enabled for both KVM
and MSHV.
Signed-off-by: Muminul Islam <muislam@microsoft.com>
This commit removes the SGX support from cloud hypervisor. SGX support
was deprecated in May as part of #7090.
Signed-off-by: Shubham Chakrawar <schakrawar@crusoe.ai>
This is the first change to Cloud Hypervisor in a series of changes
intended to increase the max number of supported vCPUs in guest VMs,
which is currently limited to 255 (254 on x86_64).
No user-visible/behavior changes are expected as a result of
applying this patch, as the type of boot_cpus and related
fields in config structs remains u8 for now, and all configuration
validations remain the same.
Signed-off-by: Barret Rhoden <brho@google.com>
Signed-off-by: Neel Natu <neelnatu@google.com>
Signed-off-by: Ofir Weisse <oweisse@google.com>
Signed-off-by: Peter Oskolkov <posk@google.com>
When the main fuzzer function returns (), it is equivalent to
returning Corpus::Keep.
In some of the return paths, we want to reject the input so that the
libfuzzer won't spend more time mutating them.
The should make fuzzing more efficient. No functional change intended.
Signed-off-by: Wei Liu <liuwe@microsoft.com>
By introducing `imports_granularity="Module"` format strategy,
effectively groups imports from the same module into one line or block,
improving maintainability and readability.
Signed-off-by: Ruoqing He <heruoqing@iscas.ac.cn>
This patch removes locks in VmCreate request and VmInfo response
since we needn't use a lock here and should ensure that internal
implementation is transparent to the runtime.
Signed-off-by: Songqian Li <sionli@tencent.com>
Pvmemcontrol provides a way for the guest to control its physical memory
properties, and enables optimizations and security features. For
example, the guest can provide information to the host where parts of a
hugepage may be unbacked, or sensitive data may not be swapped out, etc.
Pvmemcontrol allows guests to manipulate its gPTE entries in the SLAT,
and also some other properties of the memory map the back's host memory.
This is achieved by using the KVM_CAP_SYNC_MMU capability. When this
capability is available, the changes in the backing of the memory region
on the host are automatically reflected into the guest. For example, an
mmap() or madvise() that affects the region will be made visible
immediately.
There are two components of the implementation: the guest Linux driver
and Virtual Machine Monitor (VMM) device. A guest-allocated shared
buffer is negotiated per-cpu through a few PCI MMIO registers, the VMM
device assigns a unique command for each per-cpu buffer. The guest
writes its pvmemcontrol request in the per-cpu buffer, then writes the
corresponding command into the command register, calling into the VMM
device to perform the pvmemcontrol request.
The synchronous per-cpu shared buffer approach avoids the kick and busy
waiting that the guest would have to do with virtio virtqueue transport.
The Cloud Hypervisor component can be enabled with --pvmemcontrol.
Co-developed-by: Stanko Novakovic <stanko@google.com>
Co-developed-by: Pasha Tatashin <tatashin@google.com>
Signed-off-by: Yuanchu Xie <yuanchu@google.com>
This requires stashing the config values in `struct Vmm`. The configs
should be validated before before creating the VMM thread. Refactor the
code and update documentation where necessary.
The place where the rules are applied remain the same.
Signed-off-by: Wei Liu <liuwe@microsoft.com>
Users can use this parameter to pass extra paths that 'vmm' and its
child threads can use at runtime. Hotplug is the primary usecase for
this parameter.
In order to hotplug devices that use local files: disks, memory zones,
pmem devices etc, users can use this option to pass the path/s that will
be used during hotplug while starting cloud-hypervisor. Doing this will
allow landlock to add required rules to grant access to these paths when
cloud-hypervisor process starts.
Signed-off-by: Praveen K Paladugu <prapal@linux.microsoft.com>
Signed-off-by: Wei Liu <liuwe@microsoft.com>
Users can use this cmdline option to enable/disable Landlock based
sandboxing while running cloud-hypervisor.
Signed-off-by: Praveen K Paladugu <prapal@linux.microsoft.com>
Enable the use of the vmm crate with the "guest_debug" feature and make
the code that exercises that in the fuzzer unconditional on
"guest_debug" as a feature (as that is not specified as a feature in the
fuzz workspace itself.)
Signed-off-by: Rob Bradford <rbradford@rivosinc.com>
When using multiple PCI segments, the 32-bit and 64-bit mmio
aperture is split equally between each segment. Add an option
to configure the 'weight'. For example, a PCI segment with a
`mmio32_aperture_weight` of 2 will be allocated twice as much
32-bit mmio space as a normal PCI segment.
Signed-off-by: Thomas Barrett <tbarrett@crusoeenergy.com>
This commit adds the debug-console (or debugcon) device to CHV. It is a
very simple device on I/O port 0xe9 supported by QEMU and BOCHS. It is
meant for printing information as easy as possible, without any
necessary configuration from the guest at all.
It is primarily interesting to OS/kernel and firmware developers as they
can produce output as soon as the guest starts without any configuration
of a serial device or similar. Furthermore, a kernel hacker might use
this device for information of type B whereas information of type A are
printed to the serial device.
This device is not used by default by Linux, Windows, or any other
"real" OS, but only by toy kernels and during firmware development.
In the CLI, it can be configured similar to --console or --serial with
the --debug-console parameter.
Signed-off-by: Philipp Schuster <philipp.schuster@cyberus-technology.de>
These Default implementations either don't produce valid configs, are
no longer used outside of tests, or both.
For the tests, we can define our own local "default" values that make
the most sense for the tests, without worrying about what's
a (somewhat) sensible "global" default value.
Signed-off-by: Alyssa Ross <hi@alyssa.is>
Uses of the old ApiRequest enum conflated two different concerns:
identifying an API request endpoint, and storing data for an API
request. This led to ApiRequest values being passed around with junk
data just to communicate a request type, which forced all API request
body types to implement Default, which in some cases doesn't make any
sense — what's the "default" path for a vhost-user socket? The
nonsensical Default values have led to tests relying on being able to
use nonsensical data, which is an impediment to adding better
validation for these types.
Rather than having API request types be represented by an enum, which
has to carry associated body data everywhere it's used, it makes more
sense to represent API request types as trait objects. These can have
an associated type for the type of the request body, and this makes it
possible to pass API request types and data around as siblings in a
type-safe way without forcing them into a single value even where it
doesn't make sense. Trait objects also give us dynamic dispatch,
which lets us get rid of several large match blocks.
To keep it possible to fuzz the HTTP API, all the Vmm methods called
by the HTTP API are pulled out into a trait, so the fuzzer can provide
its own stub implementation of the VMM.
Signed-off-by: Alyssa Ross <hi@alyssa.is>
Fuzz the HTTP API handling code with a minimum HTTP API
receiver (e.g. mocking the behavior of our "vmm" thread).
Signed-off-by: Bo Chen <chen.bo@intel.com>
